Ember.js MutableArray insertAt() Method

Ember.js is an open-source JavaScript framework used for developing large client-side web applications which is based on Model-View-Controller (MVC) architecture. Ember.js is one of the most widely used front-end application frameworks. It is made to speed up development and increase productivity. Currently, it is utilized by a large number of websites, including Square, Discourse, Groupon, Linked In, Live Nation, Twitch, and Chipotle.

The insertAt() method is used to insert an object in a specific position in the array.

Syntax:

insertAt(idx,obj)

Parameters:

• idx: The index where the insertion operation will take place.
• obj: The object to be inserted.

Return Value: The receiver.

Step 1: To run the following examples you will need to have an ember project with you. To create one, you will need to install ember-cli first. Write the below code in the terminal:

npm install ember-cli

Step 2: Now you can create the project by typing in the following piece of code:

ember new <project-name> --lang en

To start the server, type:

ember serve

Example 1: Type the following code to generate the route for this example:

ember generate route list

app/routes/list.js

import Route from "@ember/routing/route";

export default class ListRoute extends Route {
    list = ["a", "a", "v", "c", "c", "a",
        "d", "q", "b", "z", "a"];
    item;
    idx;
    model() {
        return this.list;
    }
    setupController(controller, model) {
        super.setupController(controller, model);
        controller.set("list", this.list);
        controller.set("item", this.item);
        controller.set("idx", this.idx);
    }
}

app/controllers/list.js

import Ember from "ember";
import {
    clear, insertAt, indexOf, lastIndexOf,
    includes
} from "@ember/array";

export default Ember.Controller.extend({
    actions: {
        insertItem(item, idx) {
            this.list.insertAt(idx, item);
        },
        getLastIndex(item) {
            let res = this.list.lastIndexOf(item);
            alert(res);
        },
        getFirstIndex(item) {
            let res = this.list.indexOf(item);
            alert(res);
        },
        clearList() {
            this.list.clear();
        },
        contains(item) {
            let res = this.list.includes(item);
            alert(`The list ${res ? "" : "does not"}
       contains ${item}`);
        },
    },
});

app/template/list.hbs

{{page-title "List"}}
<h3>Here is a list of Items: </h3>
<ul>
    {{#each @model as |i|}}
        <li>{{i}}</li>
    {{/each}}
</ul>
<br /><br />
<div>
    <label>Enter Item: </label>
    {{input value=this.item}}
</div>
<div>
    <label>Enter Index: </label>
    {{input value=this.idx}}
</div>
<div>
    <input
        type="button"
        id="insert-item"
        value="Insert Item"
        {{action "insertItem" this.item this.idx}}
    />
</div>
<br /><br />
<div>
    <label>Enter Item: </label>
    {{input value=this.item}}
</div>
<div>
    <input
        type="button"
        id="first-index-item"
        value="Get First Index"
        {{action "getFirstIndex" this.item}}
    />
</div>
<div>
    <input
        type="button"
        id="last-index-item"
        value="Get Last Index"
        {{action "getLastIndex" this.item}}
    />
</div>
<div>
    <input
        type="button"
        id="contains-item"
        value="Contains?"
        {{action "contains" this.item}}
    />
</div>
<br /><br />
<input type="button" id="clear-items" value="Clear"
    {{action "clearList"}} />
{{outlet}}

Output: Visit localhost:4200/list to view the output

Example 2: Type the following code to generate the route for this example:

ember generate route party

app/routes/party.js

import Route from "@ember/routing/route";

export default class PartyRoute extends Route {
    partyItems = [
        "Digital Camera",
        "Jugs, cups & straws",
        "Cold Drink",
        "Balloons",
        "Scissors",
        "Wine",
        "Cold Drink",
        "Table Confetti",
        "Party Hats",
        "Wine",
        "Napkins",
        "Party Plates",
        "Speakers",
        "Wine",
        "Music System",
        "Cold Drink",
        "Cups",
    ];
    item;
    idx;
    model() {
        return this.partyItems;
    }
    setupController(controller, model) {
        super.setupController(controller, model);
        controller.set("partyItems", this.partyItems);
        controller.set("item", this.item);
        controller.set("idx", this.idx);
    }
}

app/controllers/party.js

import Ember from "ember";
import { insertAt, indexOf, lastIndexOf, includes }
    from "@ember/array";

export default Ember.Controller.extend({
    actions: {
        insertItem(item, idx) {
            this.partyItems.insertAt(idx, item);
        },
        getLastIndex(item) {
            let res = this.partyItems.lastIndexOf(item);
            alert(res);
        },
        getFirstIndex(item) {
            let res = this.partyItems.indexOf(item);
            alert(res);
        },
        clearpartyItems() {
            this.partyItems.clear();
        },
        contains(item) {
            let res = this.partyItems.includes(item);
            alert(`The partyItems ${res ? "" : "does not"}
       contains ${item}`);
        },
    },
});

app/template/party.hbs

{{page-title "Party"}}
<h3>Here is a list of items: </h3>
<ul>
    {#each @model as |party|}}
        <li>{{party}}</li>
    {{/each}}
</ul>
<br /><br />
<div>
    <label>Enter Item: </label>
    {{input value=this.item}}
</div>
<div>
    <label>Enter Index: </label>
    {{input value=this.idx}}
</div>
<div>
    <input
        type="button"
        id="insert-item"
        value="Insert Item"
        {{action "insertItem" this.item this.idx}}
    />
</div>
<br /><br />
<div>
    <label>Enter Item: </label>
    {{input value=this.item}}
</div>
<div>
    <input
        type="button"
        id="first-index-item"
        value="Get First Index"
        {{action "getFirstIndex" this.item}}
    />
</div>
<div>
    <input
        type="button"
        id="last-index-item"
        value="Get Last Index"
        {{action "getLastIndex" this.item}}
    />
</div>
<div>
    <input
        type="button"
        id="contains-item"
        value="Contains?"
        {{action "contains" this.item}}
    />
</div>
<br /><br />
{{outlet}}

Output: Visit localhost:4200/party to view the output

Reference: https://api.emberjs.com/ember/4.4/classes/MutableArray/methods